About 40% of the total mineral mass of bones is calcium, making it the most abundant mineral in the body. In bone, it is combined with phosphorus, as well as oxygen and hydrogen, in a mineral compound called hydroxyapatite. Calcium is also present in the fluids in the body, and there it occurs in the form of dissolved ions. An ion is an atom that carries a very small electrical charge, which can be either positive (+) or negative (−), depending on the ion.

Folate is a generic name for a group of related compounds. The name ‘folate’ was based on the word ‘foliage’, after it was identified in a crude extract from spinach, though it is also found in liver, other green vegetables, oranges and potatoes and it is often added to breakfast cereals (usually listed as folic acid). Folate is less sensitive to heat than many of the B vitamins, though it is destroyed if food is reheated or kept hot for long periods. Folate is involved in amino acid

Introduction to linear equations and matrices In this free course, matrices are used as a concise way of representing systems of linear equations which occur frequently in mathematics. Section 1 looks at simultaneous linear equations in two and three unknowns and then generalises the ideas to systems of linear equations. Section 2 develops a strategy for solving systems of linear equations. Section 3 looks at the algebra of matrices and shows that matrices can be thought of as a generalisation of vectors. Section 4 introduces the inverse ofAuthor(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

No related items provided in this feed

Introduction to differentiation This free course is an introduction to differentiation. Section 1 looks at gradients of graphs and introduces differentiation from first principles. Section 2 looks at finding derivatives of simple functions. Section 3 introduces rates of change by looking at real life situations. Section 4 looks at using the derivative of a function to deduce useful facts for sketching its graph. Section 5 covers the second derivative test, used to determine the nature of stationary points and ends by looking aAuthor(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

As we stated in Section 1, our aim is to classify surfaces up to homeomorphism. So it is worthwhile spending a little time examining what sorts of transformations of surfaces are homeomorphisms. We shall restrict the description to surfaces in space, as these are easier to deal with, though the result at the end of this subsection applies to all surfaces.

Recall that a homeomorphism between two topological spaces (such as surfaces in space) is a bijection with the property that b

We need not restrict ourselves to rectangles: we can also build surfaces by identifying edges of other polygons. For example, if we start with a pentagon and identify two pairs of its edges as shown in Figure 33, what do we get? Identifying the edges labelled a and c in the directions indicated, we obtain a cylinder with

Let us now return to the cylinder we obtained in Figure 27. What happens if we bend it around and glue the two ends? Now, continuing with our idea of identifying edges of our original rectangle, we want to bend the cylinder round and glue its ends in such a way that the points A and B are identified. Furthermore, bending

The versatile tiny transistor is now at the heart of the electronics industry. In the video clips you have seen the history of the incredible shrinking chip, its Scottish connections, and an explanation of the physics that make chips work as well as a reconstruction of making a transistor using the crude techniques of yesteryear.

In their doughnut-shaped representation, toruses can be thought of as being hollow tubes. Many other surfaces in space can also be drawn as if they were made of hollow tubing. Figure 15 shows two such examples.

Developing high trust work relationships Learn about trust in the organisational context. This free course, Developing high trust work relationships, introduces the concept of trust, what it means to you and how it may affect your organisation. First published on Mon, 12 Sep 2016 as Author(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

No related items provided in this feed

Asset allocation in investment This course looks at how to take investor objectives and constraints and turn them into a portfolio which aims at achieving an expected return and level of risk appropriate for the investor. In this free course, Asset allocation in investment, portfolio optimisation techniques such as portfolio theory can be used to determine how much of an investor’s portfolio to put in each asset class. Portfolio theory can also be used to determine so-called model portfolios which offer optimised benchmarksAuthor(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Population ageing: a global health crisis? This free course, Population ageing: a global health crisis?, focuses on two major issues of our time – ageing societies and global health. It provides you with an introduction to ageing societies and their implications for global health – implications which are only just beginning to be fully understood. The course will help you to deepen your understanding of ageing societies across the globe and the different components of the concept of global health. You will also explore the ways in whAuthor(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

No related items provided in this feed

Digital forensics Digital evidence features in just about every part of our personal and business lives. Legal and business decisions hinge on having timely data about what people have actually done. This free course, Digital forensics, is an introduction to computer forensics and investigation, and provides a taster in understanding how to conduct investigations to correctly gather, analyse and present digital evidence to both business and legal audiences. It also outlines the tools to locate and analyse digitalAuthor(s): Creator not set

License information

Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2